Projection display device

ABSTRACT

A projection display device includes light source device including a plurality of lamp units; a plurality of lamp covers for covering a plurality of lamp apertures through which respective lamp units are taken in and out; a plurality of lamp power source units for driving respective lamp units; temperature switch for detecting the temperature of light source device; and main control unit. When at least one lamp unit is turned off during operation by opening of corresponding lamp cover, main control unit continues the operation. When at least one lamp unit is turned off during operation by temperature detection of temperature switch or abnormal operation of lamp power source unit, the main control unit stops the operation.

This application is a U.S. National Phase Application of PCTInternational Application PCT/JP2011/075028.

TECHNICAL FIELD

The present invention relates to a projection display device thatmodulates light from light sources and projects the modulated light ontoa projection surface.

BACKGROUND ART

Conventionally, in a projection display device (hereinafter referred toas “projector”), e.g. a liquid crystal projector, light modulated by alight modulation element, e.g. a liquid crystal panel, is projected ontoa projection surface by a projection lens. Examples of a light sourceinclude a lamp. When a lamp is used for an extended period of time, thelamp deteriorates. Thus, after having reached its end of life, the lampneeds to be replaced with a new one.

A projector main body can include apertures through which respectivelamps are taken in and out. In this case, each lamp aperture is coveredwith a corresponding cover. When replacing a lamp, the user opens thecover and takes out the lamp.

In such a projection display device, generally, a lamp is replaced onlywhen the operation is stopped. Thus, when the cover is opened during theoperation, the lamp is turned off and thereafter the operation isstopped. Also, when a lamp overheats during the operation or the driverfor driving the lamp does not operate normally, the lamp is turned offand thereafter the operation is stopped. That is, opening of the coveris handled as an abnormality similar to abnormal temperature of the lampand abnormal operation of the lamp driver. Thus, the same operation,i.e. stopping the operation, is performed.

In order to increase the intensity, such a projector can be configuredso as to include a plurality of lamps, which is called a multi-lampconfiguration (see Patent Literature 1, for example). In a multi-lampprojector, when the end of life or a failure makes one lamp unlit, theintensity of an image decreases, but the operation can be continued withthe remaining lamps in operation. Thus, the multi-lamp projector can beconfigured such that an unlit lamp can be replaced not when theoperation is stopped as described above, but while the operation iscontinued.

CITATION LISTS Patent Literature

-   Patent Literature 1: Japanese Patent Unexamined Publication No.    2007-293033

SUMMARY OF THE INVENTION

A projection display device of the present invention includes thefollowing elements:

a light source device including a plurality of light sources andcombining light from the light sources such that the combined lightemits from the light source device;

a light modulator for modulating the light having emitted from the lightsource device;

a main body cabinet having the light source device and the lightmodulator disposed therein;

a plurality of apertures disposed in the main body cabinet such that therespective light sources are taken in and out therethrough;

a plurality of light source covers for covering the respectiveapertures;

a plurality of light source drivers disposed correspondingly to therespective light sources and driving the respective light sources;

a plurality of opening and closing detectors disposed correspondingly tothe respective light source covers and detecting opening of therespective light source covers;

a temperature detector for detecting a temperature of the light sourcedevice;

a plurality of abnormal operation detectors for detecting that therespective light source drivers do not operate normally; and

a control unit.

The control unit controls the operation in the following manner. When atleast one of the light sources is turned off by the opening of acorresponding one of the light source covers while the light sourcedevice and the light modulator operate so as to project an image, theprojection operation is continued. When at least one of the lightsources is turned off by the temperature detection of the temperaturedetector while the light source device and the light modulator operateso as to project an image, the projection operation is stopped. When atleast one of the light sources is turned off by the abnormal operationof a corresponding one of the light source drivers while the lightsource device and the light modulator operate so as to project an image,the projection operation is stopped.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an external configuration of a projector inaccordance with an exemplary embodiment of the present invention.

FIG. 2 is a drawing showing an internal structure of the projector inaccordance with the exemplary embodiment.

FIG. 3 is a diagram showing a configuration of an optical system inaccordance with the exemplary embodiment.

FIG. 4 is a drawing showing a configuration of a light source device inaccordance with the exemplary embodiment.

FIG. 5 is a drawing showing a configuration of the light source devicein accordance with the exemplary embodiment.

FIG. 6 is a diagram showing a configuration of a lamp unit in accordancewith the exemplary embodiment.

FIG. 7 is a diagram showing a configuration for detecting opening andclosing of a lamp cover in accordance with the exemplary embodiment.

FIG. 8 is a block diagram showing a control system for controlling thelamp units in accordance with the exemplary embodiment.

FIG. 9 is a block diagram showing a configuration of each lamp powersource unit in accordance with the exemplary embodiment.

FIG. 10 is a diagram showing a wiring state of V2 signal line on whichtemperature switches and second detection switches are disposed inaccordance with the exemplary embodiment.

FIG. 11 is a diagram showing a wiring state of V1 signal line on whichfirst detection switches are disposed in accordance with the exemplaryembodiment.

FIG. 12 is a diagram showing a wiring state of V2 signal line on asub-circuit board in accordance with the exemplary embodiment.

FIG. 13 is a diagram showing a wiring state of V1 signal line on thesub-circuit board in accordance with the exemplary embodiment.

FIG. 14 is a diagram showing a state where a first cable through atwelfth cable are connected to the sub-circuit board in accordance withthe exemplary embodiment.

FIG. 15 is a flowchart showing processing procedure for protectioncontrol of the lamp units in accordance with the exemplary embodiment.

FIG. 16 is a table showing states of opening and closing signals and PFCerror signals corresponding to the respective lamp units when theprojector is in various states in accordance with the exemplaryembodiment.

FIG. 17 is a diagram showing a configuration of a projector inaccordance with a modification of the present invention.

FIG. 18 is a diagram showing a configuration of a projector inaccordance with another modification of the present invention.

DESCRIPTION OF EMBODIMENT

Hereinafter, a projector in accordance with an exemplary embodiment isdescribed with reference to the accompanying drawings.

<Overall Configuration of Projector>

FIG. 1 is a diagram showing an external configuration of the projector.The projector of the exemplary embodiment includes four lamp units,which is a large projector called a four-lamp type.

Referring to FIG. 1, the projector includes main body cabinet 1 shapedinto a substantially rectangular parallelepiped. Main body cabinet 1 isformed of lower cabinet 2 and upper cabinet 3 that covers lower cabinet2 from the upper direction.

Projection window 4 is formed in the front center of upper cabinet 3.The front face of projection lens 5 is exposed to the outside throughprojection window 4.

Main cover 6 that covers a main opening is disposed in upper cabinet 3from the front face to the top face thereof. The main opening isdisposed for replacement of projection lens 5 or a prism unit,adjustment of polarizing plates, or the like. Four lamp covers 7 thatcover respective four lamp apertures are disposed in the top backportion of upper cabinet 3. Each of the lamp apertures is disposed abovethe corresponding lamp unit such that the lamp unit is replacedtherethrough.

Further, input/output terminal part 8 is disposed on the right side faceof upper cabinet 3. Various audio visual (AV) terminals are disposed ininput/output terminal part 8, and AV signals are input through the AVterminals.

Two handles 9 are disposed on each of the right and left side faces oflower cabinet 2. Handles 9 are used when the projector is carried.

FIG. 2 is a drawing that shows an internal structure of the projectorwith upper cabinet 3 thereof removed.

Referring to FIG. 2, light source device 10 and optical system 11 aredisposed inside lower cabinet 2. The optical system modulates the lighthaving emitted from light source device 10 and generates image light.

Light source device 10 is disposed in the back portion of lower cabinet2. Optical system 11 is disposed on the front side of light sourcedevice 10. Optical system 11 is disposed on lower cabinet 2 such thatprism unit 12 is attachable and detachable to and from optical system 11from the upward direction. The configurations of light source device 10and optical system 11 will be detailed later.

Projection lens 5 is disposed on the front side of optical system 11.Projection lens 5 magnifies the image light generated by optical system11 and projects the magnified image onto a projection surface, such as ascreen.

First lamp power source unit 13 is disposed on the left side of opticalsystem 11. Second lamp power source unit 14 is disposed on the rightside of light source device 10. First lamp power source unit 13 includestwo lamp power source units for supplying electric power to two frontand back lamp units, respectively, on the left side. Second lamp powersource unit 14 includes two lamp power source units for supplyingelectric power to two front and back lamp units, respectively, on theright side. Main power source unit 15 is disposed on the front side ofsecond lamp power source unit 14. Main power source unit 15 supplieselectric power to electrical components (e.g. liquid crystal panels)forming optical system 11, and to control circuit board 16, for example.

Control circuit board 16 is disposed above optical system 11. Controlcircuit board 16 includes a control circuit for controlling theelectrical components, such as liquid crystal panels and lamp units. InFIG. 2, control circuit board 16 is shown by a broken line such thatoptical system 11 is visible.

<Configuration of Optical System>

FIG. 3 is a diagram showing a configuration of optical system 11. Asshown in FIG. 3, optical system 11 includes light-guiding optical system101, three transmissive liquid crystal panels 102, 103, and 104, anddichroic prism 105. A polarizing plate (not shown) is disposed on theincident side and the emit side of each of liquid crystal panels 102,103, and 104.

White light having emitted from light source device 10 goes intolight-guiding optical system 101. Light-guiding optical system 101includes a fly's eye integrator, a PBS array, a condenser lens, dichroicmirrors, planar mirrors, and relay lenses. The white light incident onlight-guiding optical system 101 is separated into a light beam in thered wavelength band (hereinafter “R light”), a light beam in the greenwavelength band (hereinafter “G light”), and a light beam in the bluewavelength band (hereinafter “B light”). Liquid crystal panels 102, 103,and 104 are irradiated with the respective light beams. The R light, Glight, and B light having modulated by liquid crystal panels 102, 103,and 104, respectively, are color-combined by dichroic prism 105 and emittherefrom as image light. Liquid crystal panels 102, 103, and 104, anddichroic prism 105 are integrated so as to form prism unit 12.

Examples of a light modulation element forming optical system include areflective liquid crystal panel and a micro-electro-mechanical system(MEMS) device other than the above transmissive liquid crystal panels102, 103, and 104. Instead of the above three-plate type optical systemthat includes three light modulation elements, a one-plate type opticalsystem that includes one light modulation element and a color wheel maybe used.

<Configuration of Light Source Device>

FIG. 4 and FIG. 5 are drawings showing a configuration of light sourcedevice 10. FIG. 4 is a perspective view showing the state where two lampunits 300 are removed from lamp mounting unit 200. FIG. 5 is aperspective view showing the state where mirror cover 250 is removed.

Referring to FIG. 4 and FIG. 5, light source device 10 includes lampmounting unit 200 fixed to lower cabinet 2 and four lamp units 300mounted in lamp mounting unit 200.

Lamp mounting unit 200 includes housing 210, two mirror members 220,four first UV cutting members 230, second UV cutting member 240, andmirror cover 250.

Housing 210 is formed of a resin material, and includes two mirrorpositioning parts 211 in the center and four lamp receivers 212 formedon both sides of mirror positioning parts 211. The bottom face of mirrorpositioning part 211 on the front side is lower than the bottom face ofmirror positioning part 211 on the back side. The bottom faces of thepair of right and left lamp receivers 212 on the front side are lowerthan the bottom faces of the pair of right and left lamp receivers 212on the back side. Each mirror member 220 is disposed in correspondingmirror positioning part 211. Each lamp unit 300 is mounted incorresponding lamp receiver 212.

In each mirror member 220, V-shaped planar mirror 222 is mounted on thefront face of V-shaped base member 221. Mirror member 220 reflects thelight having emitted from corresponding lamp units 300 and guides thereflected light to the front direction.

Each of first UV cutting members 230 includes UV cutting glass 231 forblocking the passage of ultraviolet rays. Each first UV cutting member230 is disposed between lamp receiver 212 and corresponding mirrorpositioning part 211.

Second UV cutting member 240 is a UV cutting glass for blocking thepassage of ultraviolet rays, and disposed on the front side of frontmirror positioning part 211. Second UV cutting member 240 is higher thanthe optical path of the light that is reflected by mirror member 220 onthe back side and goes forward.

Mirror cover 250 is disposed over mirror positioning parts 211. On theright and left sides of the front part of mirror cover 250, side part251 is formed so as to extend to the top end of corresponding first UVcutting member 230. Each of side parts 251 has receiver 252 forreceiving flange 326 a of corresponding lamp unit 300 when lamp unit 300is mounted in lamp receiver 212. Guide rib 253 extends from eachreceiver 252 and positioning pin 254 protrudes therefrom. Mirror cover250 further has receivers 255 on the right and left sides of the backpart thereof. Guide rib 257 is formed on guide plate 256 that extendsupward from each receiver 255. Positioning pin 258 is formed on eachreceiver 255.

Sub-circuit board 17 is mounted on the top face of mirror cover 250.Sub-circuit board 17 includes first detection switches 401 and seconddetection switches 405 for detecting opening and closing of respectivelamp covers 7. Examples of each of detection switches 401 and 405include a microswitch. First detection switch 401 and second detectionswitch 405 are disposed adjacent to each other correspondingly to eachlamp cover 7.

FIG. 6 is a diagram showing a configuration of lamp unit 300. FIG. 6( a)is a perspective view of lamp unit 300 as viewed from a front obliquedirection. FIG. 6( b) is a perspective view of lamp unit 300 as viewedfrom a rear oblique direction.

Referring to FIG. 6, lamp unit 300 includes lamp 310 and lamp holder 320for holding lamp 310. Lamp 310 has arc tube 311 for emitting whitelight, and reflector 312 for reflecting the white light emitted from arctube 311. Examples of lamp 310 include an ultrahigh pressure mercurylamp and a xenon lamp.

Lamp holder 320 is formed of a resin material, and has holder body 321and bottom plate 322. On the front face of holder body 321, emit window323 is formed such that the light from lamp 310 emits therefrom.Heat-resistant glass plate 324 is fitted in emit window 323. The bottomface of holder body 321 is open such that lamp 310 is mounted from thebottom direction. Bottom plate 322 is attached to the front half of thebottom face of holder body 321 so as to support the bottom part of lamp310.

Handle 325 is disposed on the top face of holder body 321. Handle 325 isused when lamp unit 300 is carried, or attached to or detached from lampmounting unit 200. Lamp fixation part 326 is disposed on the front sideof handle 325. Lamp fixation part 326 has flange 326 a formed at the topend thereof. Guide groove 326 b, positioning hole 326 c, and threadedscrew hole 326 d are formed in flange 326 a. Screw 340 is inserted intothreaded screw hole 326 d.

As shown in FIG. 4, each lamp unit 300 is inserted in corresponding rampreceiver 212 in the state where the front side thereof (the side of emitwindow 323) faces mirror positioning part 211. At this time, guidegroove 326 b of flange 326 a is placed along guide rib 253 (257) ofmirror cover 250.

When each lamp unit 300 is completely mounted in lamp receiver 212,flange 326 a of lamp unit 300 makes contact with receiver 252 (255) ofmirror cover 250, and positioning pin 254 (258) fits into positioninghole 326 c of flange 326 a. Screw 340 inserted in threaded screw hole326 d fixes flange 326 a to receiver 252 (255) (see FIG. 4). Thus, lampunits 300 are fixed to lamp mounting unit 200.

When the projector operates in the state where four lamp units 300 aremounted in lamp mounting unit 200, light emits from each lamp unit 300.As shown in FIG. 5, the light having emitted from each lamp unit 300passes through corresponding first UV cutting member 230. At this time,ultraviolet rays are removed. The light having passed through each firstUV cutting member 230 is reflected by mirror member 220 corresponding tolamp unit 300, and combined into a single light beam and goes forward.The pair of lamp units 300 on the front side are disposed at a positionlower than that of the pair of lamp units 300 on the back side. Thus,the light from back lamp units 300 is not interrupted by front lampunits 300. The combined light beam passes through second UV cuttingmember 240, where the ultraviolet rays are further removed. Thus, thelight from four lamp units 300 is combined and thereby high-intensitylight emits from light source device 10.

<Configuration for Detecting Opening and Closing of Lamp Cover>

FIG. 7 is a diagram showing a configuration for detecting opening andclosing of lamp cover 7, which is a sectional view of an essential partof upper cabinet 3 taken along the right-left direction in the positionof lamp covers 7. FIG. 7 (a) shows the state where a pair of right andleft lamp covers 7 are closed. FIG. 7 (b) shows the state where one ofthe pair of right and left lamp covers 7 is opened. FIG. 7 (c) is adiagram showing an essential part of pressing flat spring 403 as viewedfrom the front direction in order to show the relation between firstdetection switch 401, second detection switch 405, and the tip ofpressing flat spring 403. In FIG. 7 (c), pressing flat spring 403 isshown by an alternate long and short dash line for convenience. FIG. 7shows the part of a pair of right and left lamp covers 7 on one of thefront and back sides. The part of the pair of right and left lamp covers7 on the other side has the identical structure.

Referring to FIG. 7, rotary shaft P of each of the right and left lampcovers 7 is set in the front-back direction along the edge of lampaperture 3 a on the side of mirror positioning part 211. Lamp cover 7rotates with rotary shaft P at the center thereof so as to open or closecorresponding lamp aperture 3 a.

Lamp cover 7 has lever 7 a formed at the end on the side of rotary shaftP (on the side of mirror positioning part 211). Lever 7 a has protrusion7 b formed thereon. Pressing flat springs 403 made of metal are attachedto the back side of upper cabinet 3. As shown in FIG. 7 (c), the tip ofpressing flat spring 403 is located on the front side of first detectionswitch 401 and second detection switch 405 disposed on sub-circuit board17.

When each lamp cover 7 is closed as shown in FIG. 7 (a), the tip ofpressing flat spring 403 is pressed by protrusion 7 b of lever 7 a, andthus deforms toward the side of detection switches 401 and 405, whichpresses buttons 402 and 406 of detection switches 401 and 405,respectively. Thus, detection switches 401 and 405 are closed.

In contrast, when lamp cover 7 is opened as shown in FIG. 7 (b),protrusion 7 b of lever 7 a leaves from the tip of pressing flat spring403, and thus pressing flat spring 403 leaves from buttons 402 and 406of detection switches 401 and 405, respectively. Thus, detectionswitches 401 and 405 are opened.

<Configuration of Control System for Driving Lamp Units>

FIG. 8 is a block diagram showing a control system for controlling lampunits 300.

In order to drive lamp units 300, main control unit 501 and lamp controlpower source unit 502 are disposed on control circuit board 16. Fourlamp power source units 600 corresponding to four lamp units 300 aredisposed separately as first lamp power source unit 13 and second lamppower source unit 14, as described above. Further, in order to protectlamp units 300 against high temperatures, temperature switches 700 aredisposed in the projector.

Hereinafter, for the convenience of explanation, when each lamp unit 300is identified separately, lamp unit 300 on the left front side in FIG. 5is referred to as LF lamp unit 300 a. Similarly, lamp units 300 on theright front side, left back side, and right back side are referred to asRF lamp unit 300 b, LB lamp unit 300 c, and RB lamp unit 300 d,respectively. Lamp power source units 600 corresponding to LF lamp unit300 a, RF lamp unit 300 b, LB lamp unit 300 c, and RB lamp unit 300 dare referred to as LF lamp power source unit 600 a, RF lamp power sourceunit 600 b, LB lamp power source unit 600 c, and RB lamp power sourceunit 600 d, respectively. First detection switches 401 corresponding toLF lamp unit 300 a, RF lamp unit 300 b, LB lamp unit 300 c, and RB lampunit 300 d are referred to as first LF switch 401 a, first RF switch 401b, first LB switch 401 c, and first RB switch 401 d, respectively.Second detection switches 405 corresponding to LF lamp unit 300 a, RFlamp unit 300 b, LB lamp unit 300 c, and RB lamp unit 300 d are referredto as second LF switch 405 a, second RF switch 405 b, second LB switch405 c, and second RB switch 405 d, respectively. Temperature switches700 corresponding to LF lamp unit 300 a, RF lamp unit 300 b, LB lampunit 300 c, and RB lamp unit 300 d are referred to as LF temperatureswitch 700 a, RF temperature switch 700 b, LB temperature switch 700 c,and RB temperature switch 700 d, respectively. FIG. 8 bears the namesand marks that separately identify lamp units 300, lamp power sourceunits 600, first detection switches 401, second detection switches 405,and temperature switches 700.

FIG. 9 is a block diagram showing a configuration of each lamp powersource unit 600.

Each lamp power source unit 600 includes relay 601, power factorimprovement circuit 602, and lamp ballast 603.

Contact 601 a of relay 601 is connected to a commercial power supply vianoise filter 604. An alternating current (AC) voltage signal at 240V,for example, is supplied from the commercial power supply. Coil 601 b ofrelay 601 is connected to switching circuit 605. Switching circuit 605includes a transistor and two resistors. A relay drive voltage signal(V2) generated by lamp control power source unit 502 is supplied to coil601 b. The relay drive voltage signal (V2) is at 12 V, for example. Arelay control signal (RLSW) for controlling relay 601 is input toswitching circuit 605 from main control unit 501.

Power factor improvement circuit 602 improves the power factor relativeto the commercial power supply by making the current waveform analogousto the voltage waveform and approximate to a sine wave. The power factorimprovement circuit converts the AC voltage signal into a direct current(DC) voltage signal and outputs the converted signal to lamp ballast603. Power factor improvement circuit 602 includes PFC control unit. Therelay control signal (RLSW) is input to PFC control unit 602 a from maincontrol unit 501. A PFC error signal (PFCERR) that indicates whether ornot an abnormality has occurred in power factor improvement circuit 602is output from PFC control unit 602 a to main control unit 501.

Lamp ballast 603 converts the DC voltage signal received from powerfactor improvement circuit 602 to a rectangular AC voltage signalsuitable for driving lamp unit 300 (lamp 310), and supplies theconverted AC voltage signal to lamp unit 300. Thereby, lamp unit 300 isdriven. Lamp ballast 603 includes BL control unit 603 a. Based on acontrol signal (TX) from main control unit 501, BL control unit 603 acontrols the operation of lamp ballast 603. For instance, by changingthe magnitude of an AC voltage signal to be supplied to lamp unit 300,the BL control unit changes the output of lamp unit 300. BL control unit603 a obtains information on lamp unit 300, such as the lighting stateof lamp unit 300, and outputs an information signal (RX) to main controlunit 501.

A Ballast control voltage signal (V1) generated by lamp control powersource unit 502 is input to BL control unit 603 a. The ballast controlvoltage signal (V1) is at 5V, for example. BL control unit 603 aoperates lamp ballast 603 when the ballast control voltage signal (V1)is input. The BL control unit stops lamp ballast 603 when the ballastcontrol voltage signal (V1) is interrupted.

Returning to FIG. 8, four first detection switches 401 are disposed onsignal line L1 of the ballast control voltage signal (V1) (hereinafterreferred to as “V1 signal line L1”) from lamp control power source unit502 to four lamp power source units 600 (BL control units 603 a). Thatis, first LF switch 401 a is disposed on V1 signal line L1 between lampcontrol power source unit 502 and LF lamp power source unit 600 a. FirstRF switch 401 b is disposed on V1 signal line L1 between lamp controlpower source unit 502 and RF lamp power source unit 600 b. First LBswitch 401 c is disposed on V1 signal line L1 between lamp control powersource unit 502 and LB lamp power source unit 600 c. First RB switch 401d is disposed on V1 signal line L1 between lamp control power sourceunit 502 and RB lamp power source unit 600 d.

Four second detection switches 405 are disposed on signal line L2 of therelay drive voltage signal (V2) (hereinafter referred to as “V2 signalline L2”) from lamp control power source unit 502 to four lamp powersource units 600 (relays 601). That is, second LF switch 405 a isdisposed on V2 signal line L2 between lamp control power source unit 502and LF lamp power source unit 600 a. Second RF switch 405 b is disposedon V2 signal line L2 between lamp control power source unit 502 and RFlamp power source unit 600 b. Second LB switch 405 c is disposed on V2signal line L2 between lamp control power source unit 502 and LB lamppower source unit 600 c. Second RB switch 405 d is disposed on V2 signalline L2 between lamp control power source unit 502 and RB lamp powersource unit 600 d.

When each lamp cover 7 is closed and thus first detection switch 401 andsecond detection switch 405 are closed (see FIG. 7 (a)), V1 signal lineL1 and V2 signal line V2 corresponding to these detection switches 401and 405 are connected. In contrast, when lamp cover 7 is opened and thusfirst detection switch 401 and second detection switch 405 are opened(see FIG. 7 (b)), V1 signal line L1 and V2 signal line V2 correspondingto these detection switches 401 and 405 are interrupted.

When V1 signal line L1 is interrupted by first detection switch 401, theballast control voltage signal (V1) is interrupted. When V2 signal lineL2 is interrupted by second detection switch 405, the relay drivevoltage signal (V2) is interrupted.

Four temperature switches 700 are disposed in series with each other onV2 signal line L2 from lamp control power source unit 502 to four seconddetection switches 405. Each of temperature switches 700 is closed whenthe ambient temperature, i.e. a detected temperature, is equal to orlower than a predetermined threshold. The temperature switch opens whenthe detected temperature exceeds the threshold. Examples of eachtemperature switch 700 include a thermostat. When one of fourtemperature switches 700 opens, V2 signal line L2 is interrupted and therelay drive voltage signal (V2) is interrupted. As described later, eachof four temperature switches 700 is disposed in proximity tocorresponding lamp unit 300.

The ballast control voltage signal (V1) is input from the output side ofeach first detection switch 401 to main control unit 501, as an openingand closing signal (LPCV) for detecting opening and closing ofcorresponding lamp cover 7. Main control unit 501 includes a pull-downresistor (not shown) in the ports to which opening and closing signals(LPCV) are input. When first detection switch 401 is closed and thus theballast control voltage signal (V1) is input, the input port is at ahigh level. When first detection switch 401 is opened and thus theballast control voltage signal (V1) is not input, the input port is at alow level.

Suppose a high-level relay control signal (RLSW) is output from maincontrol unit 501 in the state where first detection switch 401, seconddetection switch 405, and temperature switches 700 are closed. Then, thetransistor of switching circuit 605 in lamp power source unit 600 isturned on and a current based on the relay drive voltage (V2) flows incoil 601 b of relay 601. This closes contact 601 a and supplies thepower from the commercial power supply to power factor improvementcircuit 602. Thus, as described above, power factor improvement circuit602 and lamp ballast 603 operate, thereby turning on lamp unit 300.

A high-level relay control signal (RLSW) is input to PFC control unit602 a. When power factor improvement circuit 602 operates normally inthis state, a high-level PFC error signal (PFCERR) is output from PFCcontrol unit 602 a to main control unit 501.

The ballast control voltage signal (V1) is input to BL control unit 603a and BL control unit 603 a keeps the operation of lamp ballast 603.

At this time, when lamp cover 7 is opened with lamp unit 300 turned on,first detection switch 401 and second detection switch 405 open. Whendetection switches 401 and 405 open, the relay drive voltage signal (V2)is interrupted. Thus, no current flows in coil 601 b in relay 601, whichopens contact 601 a. As a result, the supply from the commercial powersupply to power factor improvement circuit 602 is stopped. Further, theballast control voltage signal (V1) is interrupted and is not input toBL control unit 603 a. Thus, BL control unit 603 a determines that lampcover 7 is opened, and stops the operation of lamp ballast 603. In thismanner, the driving of lamp unit 300 is stopped and lamp unit 300 isturned off.

At this time, a high-level relay control signal (RLSW) is input to PFCcontrol unit 602 a, but power factor improvement circuit 602 does notoperate. Then, actually, no abnormality occurs in power factorimprovement circuit 602, but a low-level PFC error signal (PFCERR) isoutput from PFC control unit 602 a to main control unit 501. No ballastcontrol voltage signal (V1) is output from the output side of firstdetection switch 401. Thus, a low-level opening and closing signal(LPCV) is input to main control unit 501.

Also in the case where any one of temperature switches 700 opens whilelamp unit 300 is turned on, the relay drive voltage signal (V2) isinterrupted and the supply from the commercial power supply to powerfactor improvement circuit 602 is stopped. Thus, the driving of lampunit 300 is stopped. The low-level PFC error signal (PFCERR) is outputfrom PFC control unit 602 a to main control unit 501. However, in thiscase, since first detection switch 401 is closed, the ballast controlvoltage signal (V1) is output from the output side of first detectionswitch 401, and a high-level opening and closing signal (LPCV) is inputto main control unit 501.

In the case where an abnormality occurs in power factor improvementcircuit 602 while lamp unit 300 is turned on, a normal DC voltage signalis not output to lamp ballast 603, and thus the driving of lamp unit 300is stopped. Further, the low-level PFC error signal is output from PFCcontrol unit 602 a to main control unit 501. Also in this case, thehigh-level opening and closing signal (LPCV) is input to main controlunit 501.

<Configuration of Wiring for Driving Lamp Units>

FIG. 10 is a diagram showing a wiring state of V2 signal line L2 onwhich temperature switches 700 and second detection switches 405 aredisposed. FIG. 11 is a diagram showing a wiring state of V1 signal lineL1 on which first detection switches 401 are disposed. FIG. 10 and FIG.11 are schematic diagrams when the inside of the projector is viewedfrom the top. In FIG. 10, the wiring of V1 signal line L1 is omitted forconvenience. In FIG. 11, part of the wiring of V2 signal line L2 isomitted for convenience.

As shown in FIG. 10, first cable CA1 for supplying the relay drivevoltage signal (V2) from lamp control power source unit 502 is connectedto sub-circuit board 17 via first connector 801. Fourth cable CA4, fifthcable CA5, sixth cable CA6, and seventh cable CA7 are also connected tosub-circuit board 17 via first connector 801. Fourth cable CA4 leads therelay drive voltage signal (V2) output from second LF switch 405 a to LFlamp power source unit 600 a. Fifth cable CA5 leads the relay drivevoltage signal (V2) output from second RF switch 405 b to RF lamp powersource unit 600 b. Sixth cable CA6 leads the relay drive voltage signal(V2) output from second LB switch 405 c to LB lamp power source unit 600c. Seventh cable CA7 leads the relay drive voltage signals (V2) outputfrom second RB switch 405 d to RB lamp power source unit 600 d.

LF temperature switch 700 a is disposed on the lateral side of LF lampunit 300 a and in proximity to LF lamp unit 300 a. LB temperature switch700 c is disposed on the lateral side of LB lamp unit 300 c and inproximity to LB lamp unit 300 c. Temperature switches 700 a and 700 care series-connected in the mid portion of second cable CA2. Both endsof second cable CA2 are connected to sub-circuit board 17 via secondconnector 802.

RF temperature switch 700 b is disposed on the lateral side of RF lampunit 300 b and in proximity to RF lamp unit 300 b. RB temperature switch700 d is disposed on the lateral side of RB lamp unit 300 d and inproximity to RB lamp unit 300 d. Temperature switches 700 b and 700 dare series-connected in the mid portion of third cable CA3. Both ends ofthird cable CA3 are connected to sub-circuit board 17 via thirdconnector 803.

Next, as shown in FIG. 11, eighth cable CA8 for supplying the ballastcontrol voltage signal (V1) from lamp control power source unit 502 isconnected to sub-circuit board 17 via first connector 801. Ninth cableCA9, tenth cable CA10, eleventh cable CA11, and twelfth cable CA12 arealso connected to sub-circuit board 17 via first connector 801. Ninthcable CA9 leads the ballast control voltage signal (V1) output fromfirst LF switch 401 a to LF lamp power source unit 600 a. Tenth cableCA10 leads the ballast control voltage signal (V1) output from first RFswitch 401 b to RF lamp power source unit 600 b. Eleventh cable CA11leads the ballast control voltage signal (V1) output from first LBswitch 401 c to LB lamp power source unit 600 c. Twelfth cable CA12leads the ballast control voltage signal (V1) output from first RBswitch 401 d to RB lamp power source unit 600 d.

Though not shown in FIG. 10 and FIG. 11, a cable for forming a groundline is disposed between lamp control power source unit 502 andsub-circuit board 17.

FIG. 12 is a diagram showing a wiring state of V2 signal line L2 onsub-circuit board 17. FIG. 13 is a diagram showing a wiring state of V1signal line L1 on sub-circuit board 17. FIG. 12 and FIG. 13 showschematic diagrams of conductive patterns PT1 through PT12 formed onsub-circuit board 17. The specific shapes and widths, for example, ofconductive patterns PT1 through PT12 are designed appropriately foractual products. For convenience, in FIG. 12 and FIG. 13, first jack 801a, second jack 802 a, third jack 803 a, first detection switches 401 a,401 b, 401 c, and 401 d, and second detection switches 405 a, 405 b, 405c, and 405 d are shown in transparent states.

Other than first detection switches 401 a, 401 b, 401 c, and 401 d, andsecond detection switches 405 a, 405 b, 405 c, and 405 d, connectors 801a, 802 a, and 803 a on the jack sides of first connector 801, secondconnector 802, and third connector 803 (hereinafter, “first jack 801 a”,“second jack 802 a”, and “third jack 803 a”, respectively) are disposedon sub-circuit board 17.

As shown in FIG. 12, second detection switches 405 a, 405 b, 405 c, and405 d on sub-circuit board 17, the first pin to the fifth pin of firstjack 801 a, second jack 802 a, and third jack 803 a are electricallyconnected via conductive patterns PT1 through PT7. These conductivepatterns PT1 through PT7 are formed on the front side, for example, ofsub-circuit board 17.

Conductive pattern PT1 connects the first pin of first jack 801 a andthe first pin of second jack 802 a. Conductive pattern PT2 connects thesecond pin of second jack 802 a and the first pin of third jack 803 a.

Conductive pattern PT3 has three branches BR1, BR2, and BR3, where thepattern is branched. This conductive pattern connects the second pin ofthird jack 803 a and the input pins of second detection switches 405 a,405 b, 405 c, and 405 d.

Conductive pattern PT4 connects the output pin of second LF switch 405 aand the fourth pin of first jack 801 a. Conductive pattern PT5 connectsthe output pin of second RF switch 405 b and the third pin of first jack801 a. Conductive pattern PT6 connects the output pin of second LBswitch 405 c and the fifth pin of first jack 801 a. Conductive patternPT7 connects the output pin of second RB switch 405 d and the second pinof first jack 801 a.

As shown in FIG. 13, first detection switches 401 a, 401 b, 401 c, and401 d on sub-circuit board 17 and the sixth pin through the tenth pin offirst jack 801 a are electrically connected via conductive patterns PT8through PT12. These conductive patterns PT8 through PT12 are formed onthe back side, for example, of sub-circuit board 17.

Conductive pattern PT8 has three branches BR4, BR5, and BR6, where thepattern is branched. This conductive pattern connects the sixth pin offirst jack 801 a and the input pins of first detection switches 401 a,401 b, 401 c, and 401 d.

Conductive pattern PT9 connects the output pin of first LF switch 401 aand the ninth pin of first jack 801 a. Conductive pattern PT10 connectsthe output pin of first RF switch 401 b and the eighth pin of first jack801 a. Conductive pattern PT11 connects the output pin of first LBswitch 401 c and the tenth pin of first jack 801 a. Conductive patternPT12 connects the output pin of first RB switch 401 d and the seventhpin of first jack 801 a.

FIG. 14 is a diagram showing a state where first cable CA1 throughtwelfth cable CA12 are connected to sub-circuit board 17. Forconvenience, FIG. 14 shows only conductive patterns PT1 through PT7formed on the front side of sub-circuit board 17 with broken lines.

First cable CA1, and fourth cable CA4 through twelfth cable CA12 areconnected to connector 801 b on the plug side of first connector 801(hereinafter, “first plug 801 b”). First plug 801 b is connected tofirst jack 801 a. Thereby, first cable CA1 is connected to the first pinof first jack 801 a, fourth cable CA4 through seventh cable CA7 areconnected to the fourth pin, the third pin, the fifth pin, and thesecond pin of first jack 801 a.

Both ends of second cable CA2 are connected to connector 802 b on theplug side of second connector 802 (hereinafter, “second plug 802 b”).Second plug 802 b is connected to second jack 802 a. Thereby, the end ofsecond cable CA2 on the side of LF temperature switch 700 a is connectedto the first pin of second jack 802 a. The end of second cable CA2 onthe side of LB temperature switch 700 c is connected to the second pinof second jack 802 a.

Both ends of third cable CA3 are connected to connector 803 b on theplug side of third connector 803 (hereinafter, “third plug 803 b”).Third plug 803 b is connected to third jack 803 a. Thereby, the end ofthird cable CA3 on the side of RF temperature switch 700 b is connectedto the first pin of third jack 803 a. The end of third cable CA3 on theside of RB temperature switch 700 d is connected to the second pin ofthird jack 803 a.

In this manner, the relay drive voltage signal (V2) generated in lampcontrol power source unit 502 is input to the first pin of first jack801 a via first cable CA1, and to second cable CA2 via conductivepattern PT1 and the first pin of second jack 802 a. The relay drivevoltage signal (V2) input to second cable CA2 goes through LFtemperature switch 700 a and LB temperature switch 700 c, mid portion ofis input to third cable CA3 via the second pin of second jack 802 a,conductive pattern PT2, and the first pin of third jack 803 a. The relaydrive voltage signal (V2) input to third cable CA3 goes through RFtemperature switch 700 b and RB temperature switch 700 d, mid portion ofis input to the second pin of third jack 803 a. In this manner, therelay drive voltage signal (V2) is input to the second pin of third jack803 a via single wiring from first cable CA1 through third cable CA3.

The relay drive voltage signal (V2) input to the second pin of thirdjack 803 a is branched by conductive pattern PT3 and input to the inputpins of second detection switches 405 a, 405 b, 405 c, and 405 d. Therelay drive voltage signals (V2) output from the output pins of seconddetection switches 405 a, 405 b, 405 c, and 405 d are input to lamppower source units 600 a, 600 b, 600 c, and 600 d, respectively, viaconductive patterns PT4 through PT7, first connector 801, fourth cableCA4 through seventh cable CA7.

On the other hand, the ballast control voltage signal (V1) generated inlamp control power source unit 502 is input to the sixth pin of firstjack 801 a via eighth cable CA8. The ballast control voltage signal (V1)input to the sixth pin of first jack 801 a is branched by conductivepattern PT8 and input to the input pins of first detection switches 401a, 401 b, 401 c, and 401 d. The ballast control voltage signals (V1)output from the output pins of first detection switches 401 a, 401 b,401 c, and 401 d are input to lamp power source units 600 a, 600 b, 600c, and 600 d, respectively, via conductive patterns PT9 through PT12,first connector 801, and ninth cable CA9 through twelfth cable CA12.

<Protection Control of Lamp Units>

FIG. 15 is a flowchart showing processing procedure for protectioncontrol of the lamp units. FIG. 16 is a table showing the states ofopening and closing signals (LPCV_, LPCV_, LPCV_, and LPCV_) and PFCerror signals (PFCERR_, PFCERR_, PFCERR_, and PFCERR_) corresponding torespective lamp units 300 a, 300 b, 300 c, and 300 d when the projectoris in various states. In FIG. 16, “H” shows a high-level signal, and “L”shows a low-level signal.

The protection control shown in FIG. 15 is performed by main controlunit 501 while the projector is in operation, that is, lamp units 300are turned on, liquid crystal panels 102, 103, and 104 are driven, andan image is projected on a screen.

During the operation, main control unit 501 monitors the states ofopening and closing signals (LPCV) and PFC error signals (PFCERR)corresponding to lamp units 300 a, 300 b, 300 c, and 300 d. The maincontrol unit determines whether or not the opening and closing signal(LPCV) is at the high level and the PFC error signal (PFCERR) is at thelow level in any one of lamp units 300 a, 300 b, 300 c, and 300 d (S101through S104).

When the projector operates normally, opening and closing signals (LPCV)and PFC error signals (PFCERR) are at the high level as shown in FIG.16. In this case, main control unit 501 determines that the conditionwhere an opening and closing signal (LPCV) is at the high level and aPFC error signal (PFCERR) is at the low level is not satisfied (S101:No, S102: No, S103: No, and S104: No), and keeps monitoring.

In the exemplary embodiment, any one of lamp units 300 in an unlit statecaused by the end of life or a failure can be replaced while theoperation is continued. Generally, the user opens lamp cover 7 in orderto replace the lamp during the operation. However, the user may openlamp cover 7 inadvertently during the operation.

Inadvertent opening of lamp cover 7 can be determined by detecting theopening of lamp cover 7 corresponding to lamp unit 300 over which maincontrol unit 501 performs control so as to turn on the lamp unit 300.

When any one of lamp covers 7 is opened during the operation, firstdetection switch 401 and second detection switch 405 open in lamp unit300 corresponding to opened lamp cover 7. Thus, as shown in FIG. 16,both of the opening and closing signal (LPCV) and PFC error signal(PFCERR) are at the low level in the lamp unit.

At this time, as described above, in response the opening of firstdetection switch 401 and second detection switch 405, the driving ofcorresponding lamp power source unit 600 is stopped. Thus, lamp unit 300corresponding to opened lamp cover 7 is turned off such that the user isprotected. However, the other lamp units 300 are kept in the lit state.As required, part of the other lamp units 300 can be turned off, or partor the whole of the other lamp units 300 can be dimmed.

When any one of lamp covers 7 is opened, even if the lamp cover isinadvertently opened, it is only necessary to turn off at leastcorresponding lamp unit 300. Thus, also in this case, main control unit501 determines that the condition where an opening and closing signal(LPCV) is at the high level and a PFC error signal (PFCERR) is at thelow level is not satisfied (S101: No, S102: No, S103: No, and S104: No),and keeps monitoring. Since whole light source device 10 keeps operationeven when any one of lamp covers 7 is opened, the lamp can be replacedwhile the operation is continued.

When the user closes lamp cover 7, first detection switch 401 and seconddetection switch 405 are closed. Thus, corresponding lamp unit 300 isready to be turned on again, and the operation of lamp unit 300 can bestarted.

Next, if an abnormality occurs in any one of lamp units 300 or anabnormality occurs in a cooling fan (not shown) for cooling lamp units300 and thus lamp units 300 are not cooled normally, any one of or alllamp units 300 can become in an overheated state. When lamp unit 300overheats, the ambient temperature becomes high and temperature switch700 corresponding to lamp unit 300 opens.

When such an abnormal temperature occurs, at least one temperatureswitch 700 opens in a state where lamp covers 7 are closed. Thereby, asshown in FIG. 16, the opening and closing signal (LPCV) becomes at thehigh level and the PFC error signal (PFCERR) becomes at the low level ineach lamp unit 300.

Even when an abnormal temperature occurs and temperature switch 700operates only in one lamp unit 300, whole light source device 100 can bein the overheated state. Thus, keeping normal operation in this statecan be difficult.

In step S101, for example, main control unit 501 determines that theopening and closing signal (LPCV) is at the high level and the PFC errorsignal (PFCERR) is at the low level (S101: Yes), and performs protectionprocessing (S105).

Main control unit 501 performs shutdown processing for stopping theoperation, as protection processing. That is, main control unit 501turns off all lit lamp units 300 and stops the operation of liquidcrystal panels 102, 103, and 104. As required, the cooling fan may bedriven for a predetermined period until lamp units 300 are cooled andthereafter stopped. After the shutdown processing is complete and theoperation ends, main control unit 501 brings the projector into astandby state.

Next, when power factor improvement circuit 602 in any one of lamp powersource units 600 does not operate normally for some reasons, the PFCerror signal (PFCERR) from PFC control unit 602 a of corresponding powerfactor improvement circuit 602 becomes at the low level as shown in FIG.16. At this time, in lamp unit 300 corresponding abnormal lamp powersource unit 600, the opening and closing signal (LPCV) remains at thehigh level.

When an abnormality occurs even in only one lamp power source unit 600(power factor improvement circuit 602), it is not desirable that lamppower source unit 600 is left in the abnormal state while the operationis continued.

When an abnormality occurs in power factor improvement circuit 602 in LFlamp power source unit 600 a, for example, in step S101, main controlunit 501 determines that the opening and closing signal (LPCV) is at thehigh level and the PFC error signal (PFCERR) is at the low level (S101:Yes). Next, similarly to the case where an abnormal temperature occursin lamp unit 300, the main control unit performs protection processing(S105).

Advantages of the Exemplary Embodiment

As described above, in accordance with the exemplary embodiment, theoperation is controlled in the following manner. When any one of lampcovers 7 is opened, corresponding lamp unit 300 is turned off and theoperation is continued with the remaining lamp units 300 in operation.When any one of lamp units 300 is in an overheated state or any one oflamp power source units 600 does not operate normally, correspondinglamp unit 300 is turned off and thereafter the operation is stopped.Thus, the projection display device is capable of properly handlingopening of lamp cover 7, abnormal temperature of lamp unit 300, andabnormal operation of lamp power source unit 600 separately.

In accordance with the exemplary embodiment, when any one of lamp covers7 is opened, and a ballast control voltage signal (V1) is interrupted bycorresponding first detection switch 401 or a relay drive voltage signal(V2) is interrupted by corresponding second detection switch 405, lampunit 300 corresponding to opened lamp cover 7 is turned off. Thus, whenlamp cover 7 is opened, lamp unit 300 can be turned off precisely. Whenthe relay drive voltage signal (V2) is interrupted by second detectionswitch 405, a PFC error signal (PFCERR) is input to main control unit501. However, even when the PFC error signal (PFCERR) is input, maincontrol unit 501 does not stop operation if an opening and closingsignal (LPCV) is not input. Thus, when lamp cover 7 is opened, theoperation is not stopped erroneously.

In accordance with the exemplary embodiment, when the ballast controlvoltage signal (V1) is interrupted by first detection switch 401,corresponding lamp ballast 603 is stopped. When the relay drive voltagesignal (V2) is interrupted by second detection switch 405, correspondingrelay 601 is turned off. With this configuration, even if a failureoccurs in one of lamp ballast 603 and relay 601 (e.g. failure of lampballast 603, and adhesion of contact 601 a in relay 601), in response toopening of lamp cover 7, lamp unit 300 is turned off by one of the lampballast and the relay that has no failure. Thus, when lamp cover 7 isopened, corresponding lamp unit 300 can be turned off precisely.

Further, in accordance with the exemplary embodiment, four temperatureswitches 700 corresponding to respective lamp units 300 are disposed inseries with each other on V2 signal line L2 from lamp control powersource unit 502 to second detection switches 405. With thisconfiguration, when at least one temperature detector 700 detects anabnormal temperature in the periphery of the temperature detector 700,all lamp units 300 are turned off. This configuration can protect lightsource device 10 against abnormal temperatures more carefully.

<Others>

The present invention is not limited to the above description of theexemplary embodiment, and the exemplary embodiment of the presentinvention can be modified into various forms other than the aboveexemplary embodiment.

For instance, as shown in FIG. 17, the relay drive voltage signal (V2)may be input from the output side of temperature switches 700 to maincontrol unit 501 as an opening and closing signal (TMV) for detectingopening and closing of temperature switches 700. In this case, maincontrol unit 501 includes a pull-down resistor (not shown) in the portto which the opening and closing signal (TMV) is input. When alltemperature switches 700 are closed and thus the relay drive voltagesignal (V2) is input, the input port is at a high level. When at leastone temperature switch 700 is opened and thus no relay drive voltagesignal (V2) is input, the input port is at a low level. The opening andclosing signal (TMV) corresponds to a third detection signal of thepresent invention.

When the opening and closing signal (TMV) is at the low level, maincontrol unit 501 determines that an abnormal temperature has occurred inlight source device 10. Thus, main control unit 501 can discriminateabnormal temperature of light source device 10 from abnormal operationof power factor improvement circuit 602 when the operation is stopped byprotection control in FIG. 15. Main control unit 501 enables theinformation showing the causes of these abnormalities to be stored in amemory (not shown) or shown on a display (not shown) in the projector.Thus, in the repair of the projector, the repair worker can obtain thedetailed information on the causes of the shutdown by reading out theinformation showing the causes of abnormalities from the memory orchecking the display.

In the above exemplary embodiment, four temperature switches 700 aredisposed in series with each other on V2 signal line L2 from lampcontrol power source unit 502 to four second detection switches 405.However, as shown in FIG. 18, temperature switches 700 a, 700 b, 700 c,and 700 d may be disposed correspondingly to respective second detectionswitches 405 a, 405 b, 405 c, and 405 d on the output side of the seconddetection switches. In this case, only lamp unit 300 corresponding totemperature switch 700 that has detected an abnormal temperature isturned off.

In the above exemplary embodiment, four temperature switches 700 aredisposed correspondingly to four lamp units 300. However, theconfiguration is not limited to the above. For instance, one temperatureswitch 700 may be disposed for a pair of LF lamp unit 300 a and LB lampunit 300 c on the left side, and one temperature switch 700 may bedisposed for a pair of RF lamp unit 300 b and RB lamp unit 300 d on theright side. In this case, preferably, one temperature switch 700 isdisposed between the pair of lamp units 300. In this manner, astemperature switches corresponding to the respective lamp units, onetemperature switch may correspond to a plurality of lamp units.Alternatively, only one switch 700 may be disposed in light sourcedevice 10. In this case, it is preferable that temperature switch 700 isdisposed in a position where the temperature is the highest in lightsource device 10.

In the above exemplary embodiment, four second detection switches 405are disposed on V2 signal line L2. However, these second detectionswitches 405 may be omitted.

In the above exemplary embodiment, the light having emitted from eachlamp unit 300 is combined by reflecting the light with mirror member 220(planar mirror 222). Instead of the mirror, a prism may be used as thelight combiner.

In the above exemplary embodiment, light source device 10 is formed oflamp units 300 each including a lamp light source. However, light sourcedevice 10 may be formed of light source units each including an LEDlight source or a laser light source.

Further, the projector of the above exemplary embodiment is a four-lampprojector, but the present invention is applicable to multi-lampprojectors other than the four-lamp projector.

The exemplary embodiment of the present invention can be modified invarious ways as appropriate within the scope of the technical ideasdescribed in the claims.

REFERENCE MARKS IN THE DRAWINGS

-   ]-   1 Main body cabinet-   3 a Lamp aperture (aperture)-   7 Lamp cover (light source cover)-   10 Light source device-   11 Optical system-   102, 103, 104 Liquid crystal panel (light modulator)-   300 Lamp unit (light source)-   401 First detection switch (opening and closing detector, first    opening and closing detector)-   405 Second detection switch (opening and closing detector, second    opening and closing detector)-   501 Main control unit (control unit)-   502 Lamp control power source unit (signal supply part)-   600 Lamp power source unit (light source driver)-   601 Relay (switch)-   602 Power factor improvement circuit (signal converter)-   602 a PFC control unit (abnormal operation detector)-   603 Lamp ballast (signal converter)-   700 Temperature switch (temperature detector)

1. A projection display device, comprising: a light source deviceincluding a plurality of light sources and combining light from thelight sources such that the combined light emits from the light sourcedevice; a light modulator for modulating the light having emitted fromthe light source device; a main body cabinet having the light sourcedevice and the light modulator disposed therein; a plurality ofapertures disposed in the main body cabinet such that the respectivelight sources are taken in and out therethrough; a plurality of lightsource covers for covering the respective apertures; a plurality oflight source drivers disposed correspondingly to the respective lightsources and driving the respective light sources; a plurality of openingand closing detectors disposed correspondingly to the respective lightsource covers and detecting opening of the respective light sourcecovers; a temperature detector for detecting a temperature of the lightsource device; a plurality of abnormal operation detectors for detectingthat the respective light source drivers do not operate normally; and acontrol unit, wherein the control unit controls operation in a mannersuch that when at least one of the light sources is turned off byopening of a corresponding one of the light source covers while thelight source device and the light modulator operate so as to project animage, the projection operation is continued, when at least one of thelight sources is turned off by temperature detection of the temperaturedetector while the light source device and the light modulator operateso as to project an image, the projection operation is stopped, and whenat least one of the light sources is turned off by abnormal operation ofa corresponding one of the light source drivers while the light sourcedevice and the light modulator operate so as to project an image, theprojection operation is stopped.
 2. The projection display device ofclaim 1, comprising a signal supply part for supplying a firstelectrical signal and a second electrical signal to the respective lightsource drivers, the first electrical signal and the second electricalsignal being related to driving of the respective light sources, whereineach of the opening and closing detectors includes a first opening andclosing detector for interrupting the first electrical signal andallowing output of a first detection signal produced by the interruptionto the control unit when a corresponding one of the light source coversis opened, the temperature detector interrupts the second electricalsignal when the temperature of the light source device exceeds apredetermined threshold, each of the respective light source driversstops driving of a corresponding one of the respective light sources ina case where the first electrical signal or the second electrical signalis interrupted when the respective light sources are driven based on adriving command from the control unit, when each of the respective lightsource drivers stops the driving of a corresponding one of therespective light sources with the driving command output from thecontrol unit, a corresponding one of the abnormal operation detectorsoutputs a second detection signal produced by the stop to the controlunit, and the control unit controls operation in a manner such that whenat least one of the light sources is turned off by opening of acorresponding one of the light source covers, and thus the firstdetection signal is output from one of the first opening and closingdetectors corresponding to the unlit light source, the operation iscontinued, when at least one of the light sources is turned off bytemperature detection of the temperature detector, and thus the seconddetection signal is output from one of the abnormal operation detectorscorresponding to the unlit light source, the operation is stopped basedon the output of the second detection signal, and when at least one ofthe light sources is turned off by abnormal operation of a correspondingone of the light source drivers, and thus the second detection signal isoutput from one of the abnormal operation detectors corresponding to theunlit light source, the operation is stopped based on the output of thesecond detection signal.
 3. The projection display device of claim 2,wherein each of the opening and closing detectors includes a secondopening and closing detector disposed correspondingly to each of thelight source covers and interrupting the second electrical signal inresponse to detection of opening of the corresponding light sourcecover, and, when the second detection signal is output from one of theabnormal operation detectors corresponding to the unlit light source andthe first detection signal is not output from one of the first openingand closing detectors corresponding to the unlit light source, thecontrol unit stops the operation.
 4. The projection display device ofclaim 3, wherein each of the light source drivers includes: a signalconverter for converting a supply voltage signal supplied to each lightsource driver into a drive voltage signal suitable for driving acorresponding one of the light sources; and a switch for allowing thesupply voltage signal to be supplied to the signal converter or stoppingthe supply, according to the driving command from the control unit, thesignal converter stops operation of conversion to the drive voltagesignal when the first electrical signal is interrupted, and the switchstops the supply of the supply voltage signal to the signal converterwhen the second electrical signal is interrupted.
 5. The projectiondisplay device of claim 3, wherein the second opening and closingdetectors are disposed on a side nearer to the light source drivers thanthe temperature detector on a signal line for supplying the secondelectrical signal, and when the second electrical signal is interrupted,the temperature detector outputs a third detection signal produced bythe interruption to the control unit.
 6. The projection display deviceof claim 2, wherein the temperature detector is one of a plurality oftemperature detectors disposed correspondingly to the respective lightsources and the respective temperature detectors are disposed in serieswith each other on the signal line for supplying the second electricalsignal.
 7. The projection display device of claim 4, wherein the secondopening and closing detectors are disposed on a side nearer to the lightsource drivers than the temperature detector on a signal line forsupplying the second electrical signal, and when the second electricalsignal is interrupted, the temperature detector outputs a thirddetection signal produced by the interruption to the control unit. 8.The projection display device of claim 3, wherein the temperaturedetector is one of a plurality of temperature detectors disposedcorrespondingly to the respective light sources and the respectivetemperature detectors are disposed in series with each other on thesignal line for supplying the second electrical signal.
 9. Theprojection display device of claim 4, wherein the temperature detectoris one of a plurality of temperature detectors disposed correspondinglyto the respective light sources and the respective temperature detectorsare disposed in series with each other on the signal line for supplyingthe second electrical signal.
 10. The projection display device of claim5, wherein the temperature detector is one of a plurality of temperaturedetectors disposed correspondingly to the respective light sources andthe respective temperature detectors are disposed in series with eachother on the signal line for supplying the second electrical signal. 11.The projection display device of claim 7, wherein the temperaturedetector is one of a plurality of temperature detectors disposedcorrespondingly to the respective light sources and the respectivetemperature detectors are disposed in series with each other on thesignal line for supplying the second electrical signal.